Apparatus for producing seat pads



Jan. 15, 1952 J, R, MILLAR TAL 2,582,449

APPARATUS FOR PRODUCING SEAT PADS Filed May 22, 1950 2' SHEETS-SHEET 'l lll l INVENTORS JOHN R. MILLAR. ROBERT J.STACK BY cLENcE J.D v W /ff Y ATTORNEYS FIGA.

-J. R. MILLAR r-:TAL 2,582,449

APPARATUS FOR PRODUCING SEAT PADS Jan. 15, 1952 Filed May 22, 1950 2 SHEETS- SHEET 2 Fles.

IN VEN TORS C ARENCE JJJQV f ATTORNEYS Patented Jan. 15, 1952 *'J'ohnRMillaryfReno, Nev., and Robert J. Stack, Grossel1.oiii-te,- and Clarence. J lDaviesfDetroit,

.i Mich., .assignors to NationalrAutomotirve Fibres, Inc., Detroit;A Mich.,.a corporation of Delaware Application `Ma`y 22, 1950, Serial No. 163,541

The presentinvention relates -to apparatus 4for producing "seat pads; andfmore particularlypto f apparatus for producing-` automobile V4cushionsr` in- -cludinga shaped-ply of vulcanized:foam rubber.

i The presentv application isa continuation-inpart of our prior copending application, Serial vI\To.6'7,842, filed December-29, 11948,'--in which claims are -1 directedto-"ffthe product. yAf-c'orn- Apanion continuation-impart application, Serial v`-lNo. 163,542, -was liiled- May :22,` 1950, containing claims `direc-ted to ther-method of Amaking.l the pads,

The advantages tof-seat cushions using rfoam A rubber as a cushioning-agent are well recognized;

however, thismaterialis relatively expensive; "It Iisfound `that t-he1mo^stA important-advantages of berv `is provided in' 'the-form Aof a .relatively thin -ply at the topofE a `cushion structure. 1. However, the .-fabricationfof .Lrelativelythin npliesf off' vfoam rubber, particularly where. the :pad has y.one or more feather edgeais difficult. :'.It' has beenfound thatr in'- attempting .to lremove :such foam irubber pads. from; molds` .resulted .in. a .relativelyl high proportionof scrap. ..Moreovergfwhenzpads Vhavingthese relativelythin weakA edges :were success- .fully :removed from vthe n1`old,.:it Wascnecessary .Lto

.bind-the edgesofithe pad with an adhesive'ly applied .fabricf or Lthelike to; prevent tearingzfofitlie ,ed-ge. during :and after assemblyz in .the.seat.

' According to the present invention,.:the foam rubber 4isiapplied directly toa :supporting fabric Uwhich is retained in a-.moldandaftertheioam f rubber hasv been vulcanized the fia-bric.` and foam rubber pad are :removed as-a unit. I'hezfabric not only-reinforces the yrubber-and facilitates iits removal from 'the` mold, ,but also serves asf a mounting fabric in assemblying the' foam frubber `into a seat cushion.

In order'to furtherreduce the amount of foam rubber which is vrequired to producefa pad and toi improve thequality `of resilience `of thecornpleted pad, the foam rubber vis provided with a pluralityof upwardly extending blind holes. :In order to` permit vthe shaping `of the l foam 4rubber in thisA manner, lthe `fabric to which :it is applied isl provided with a .correspondinggplurality of holes throughv which mold kcores extend. a Preferably, the holes in: the supporting fabric lare providedfbyicross:slitting thefabric, thusprovid- .ing ears ortabs of fabrics'. whichA are. locatedinfj v.wardlyof the padbythe,A mold cores during the forming operation. These ,tabs of .fabric vaddir `tionally reinforce the foam Arubber cushion and .serve asadditional meansfor interconnectingthe t fabricand the frubber.

With the foregoingl general remarks inmind, it is an object of the present. invention to; provide 1- apparatus for producingnovel seat padsrvvhich is characterizedby the efficiency withv whichjthe `pads are produced as Well as the economy, and rapidity of production.

More specifically, it is an object of the present inventionto provide apparatus including. arnold having a: shape complementary,v .to ,the ,desired shape of the foam rubber seat pad, provided awith a plurality .ofupstandingimold core elements to:pr,oduce hollow recessesin thelnished product.

...`In.usea fabric liner. is provided having cross-cuts corresponding in number and location to the mold .coressothatwhen theliner is placedover the Nmoldcores, lthe tabs ofthe fabric extend upwardly .,alongthe. sides of the mold cores, andzin vthe ,finished product serve .as partial lining elements ifor. the recesses.

Itis a further objectof the presentinvention to provideapparatus comprising conveyor meehanism for advancing acontinuous stripA of fabric, providing amultiplicity of cross cuts in thefabric,

advancing the fabric into positionoverlying a series of shallow'moldsprovidedwith a plurality of upstanding mold;cores,means effective toiforce the fab-ricdowninto the molds and to cause'the mold ,cores to extend through-the cut yareas of the Lfabric,l means for providing unvulcanized ,foam

rubber.- in vthe `mold cores, andjmeans for therev`after vulcanizingthe foam rubber.

It is a further object of the present invention sto. provide apparatus comprising `an y.endless .con-

veyor ,-.belt having integrally formed recessed molds therein.

It is a further object of the present invention to provide a series. of molds in a continuous `conl-veyorbelt characterized by `the fact that the molds `.intermediate a pair of end-rolls retain a `denite mold form and yet are suiicien'tly4 flexible topermit lbending of themold elements. asthey pass around a roller.

`'It isa further object of the present `invention to, provide shallow` .pad forming molds having a plurality of upstanding mold `cores therein in combination with a presser having recesses shaped and positioned to receive the mold cores'in order vto press a fabric into position in the mold'with the mold Acores extending through previouslycut ar-eas ofthe fabric.

' It is a-further object of the present invention ito provide apparatus forming a plurality of -independent foam rubber padscn a single continuous strip of Woven fabric in'which the fabric v`is .einployedas the means for extracting the vul- `canizedfrubber pad from-the mold,

It is a further object of the present invention to provide a mold form f varying thickness taperingat least at one side to a feather edge, 1ncluding means for advancing a continuous strip of fabric in overlying relation to a series of molds, means for supplying unvulcanized foam rubber to the fabric liner molds, means for vulcanizing the rubber in place, and means for thereafter employing the fabric as means for extracting the vulcanized rubber pad from th-e mold without the possibility of tearing or other injury to the feather edge of the pad.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:

Figures 1 and 1A together constitute a perspective view of the apparatus for making pads.

Figure 2 is a section on the line 2-2 of Figure 1.

Figure 3 is a fragmentary section through the foam rubber applicator.

Figure 4 is a perspective view partly in section of a somewhat modied seat assembly.

Figure 5 is a transverse section through the cushion pad assembly used in the seat assembly of Figure 4.

Figure 6 is a transverse section through a reinforced foam rubber pad as it com-es from the mold.

Figure '1 is an enlarged section showing the manner in which the reinforcing fabric extends into the line of holes at the under side of the foam rubber pad.

In accordance with the present invention, seat assemblies such for example as for use in automobiles, are composed generally of a spring assembly. superimposed padding material such for example as cotton, over which is provided a relatively thin layer of foam rubber. The seat assembly is completed by covering the structure with upholstery material which normally is tacked at its edges to tacking strips provided at the under side of the seat assembly.

Referring first to Figures 4 and 5 there is illustrated a seat assembly comprising a spring frame I2, housing a plurality of coil springs I I, over the top of which is provided the usual spring insulator I2. The cushion pad assembly indicated generally at I5 is illustrated in Figure 5 and comprises brous padding material I6 which may be cotton or the like.

A separate folded cotton bat I1 is also included to provide eXtra padding at the forward edgeof the border wire I8 of the spring. The brous padding material is contained in an envelope comprising an upper reinforcing fabric I9a and a lower fabric ISb, the edges of which are permanently secured to the edges of the reinforcing fabric Iga. Permanently united with the upper surface of the reinforcing fabric I9a is a foam rubber pad 25. As a result of the method of producing the foam rubber pad, rubber material at the under side of the pad is caused to penetrate into the interstices of the fabric so as to provide an especially tight bond between the parts. In addition, the under side of the foam rubber pad is provided with a plurality of upwardly extening blind holes 2I. The reinforcing fabric ISa has openings 22 therein which register with the openings in the foam rubber pad. As a result of a preferred method of producing these blind holes, attached tabs 23 of the fabric material eX- tend upwardly and are permanently bonded to the foam rubber material at the sides of the blind holes 2I. This detail of construction is best seen in Figure 7.

In assembling the seat assembly, the cushion pad assembly I5 is placed over the spring insulator I2. A thin layer of cotton wadding 24 is provided over the upper surface of the cushion pad assembly and thereafter the upholstery fabric 25 is applied over the cushion pad assembly and its edges are drawn down around the cushion pad assembly causing the cushion pad assembly to assume the form illustrated in Figure 4. The edges of the upholstery material 25 are secured as by tacking as indicated at 26, to tacking strips 21 provided at the lower edge of the spring assembly.

The apparatus for producing the foam rubber pad and constituting one means for carrying out the improved method of production is illustrated in Figures 1 to 3. The apparatus comprises an elongated table 50 including supporting posts 5I for supporting a roll 52 of a woven fabric such for example as burlap. Adjacent the supply roll 52 is a press 54 which includes cutting elements 55 designed to cut longitudinally spaced sets of holes in the advancing web of fabric 56. Preferably, these holes are formed by crossed slits as indicated at 51. Feed rolls 60 are provided for drawing the web of fabric from the roll 52. Just beyond the feed roll 60 is a roll 62 about which a traveling endless belt mold 63 is caused to advance. The endless belt mold is formed of a suitable heat resistant material and also a material which has sufficient flexibility to permit it to pass around rolls 62 and 64 while at the same time, it has suilcient strength to retain the mold from intermediate the rolls 62 and 64. In practice, a heat resistant silicone rubber is found to be useful in forming the endless belt mold and is preferably permanently attached to a canvas belt 68 (Fig. 2). Spaced along the endless belt mold are a plurality of depressed mold portions, one of which is indicated at 65. These mold portions have a cross-sectional shape corresponding to the desired corresponding cross-sectional shape of the foam rubber pad. In this position they are provided with a plurality of upstanding mold cores 61 which are designed to form blind holes in the under side of the foam rubber pad.

Mechanism is provided for depressing the fabric web into the mold forms 65 so as to cause a portion of the web to conform to the shape of the mold and further to cause the mold cores 611 to project upwardly through the openings 51 previously cut in the fabric web. To accomplish this result a -presser 10 is provided which comprises a frame 1I and an apertured plate 12 having a plurality of openings therein corresponding in number and disposition to the mold cores 61 and the openings 51 previously formed in the fabric. The presser 10 is mounted for vertical movement with respect to a slide 13 by suitable guide means indicated at 14. The slides 13 are mounted for horizontal movement parallel to the direction of advance of the fabric web 56 on guide bars 15. Actuating racks 16 are connected to the slide 13 and are moved back and forth in timed relation to advance of the molds 65 by pinions 11. Means are provided for effecting vertical motion of the presser 10 in timed relation to advance of the molds 65 and this means comprises linkage indicated generally at 18 connected to an actuating pinion 19 in mesh with a rack bar 8D. The parts are operated in timed relation to the advance of the molds 65 and operate in the following manner: The presser 10 is depressed while .-,a. .feather edge.

-.t ,is advanced-synchronouslwwith thezvveb-v56 and mold liiinto' thelmoldfdepression. I The openx'ings'in :theiplatef12 receive thenmold cores'l and press thenmaterialof the Web-#56 down and over'the mold eores,*bymeansof-which:the fabric ,.K

is retained inthe mold. .The fabriek-thus becomesginr effect, ea vliner for the: mold forrazs pur- :zposewhich will. subsequently appear.

f Subsequently the presserV 10 isxelevatedwwhile 1 stillnadvancing @synchronously with the mold 65. z'

and thereafter returns totitsainitial. starting;- p'osi- 1iftion. s Suitable controlrm'echanismyis'provided: so ifthatas each moldi' advances beneaththe press- V1er assembly,..the presser lois actuate'dtocause -the fabricl weblto conform to? .the configuration of the mold.

'L'Thematerial subsequently-advances' beneath a trough or hopper-i239, 'con-taininga'supplyofsemi- I liquid unvulcanized llatex foam rubber indicated at-'B I. v As `-best rseen v in Figure 3, thelower `end f ofthe trough 80 has a relatively narrowineck Telescopically received over lthe open bot- The'fright hand edge of the distributor-*83 as seen in Figure 3, isprovidedwith a-sharp corner as indicated'at-M; Which'acts as a scraper and prevents deposition of foam rubber `onto the "fabricexcept Where rthe fabric is depressed into 'the molds 65. Compression springs 65 Vareprovided urging the distributor 83'down into" contact Withxthe upper surface of the fabric'. The telescopic arrangement between the distributor 83 'and the nozzle' 82 permits vthe passage' of portions of the'vveb of uneventhickness, as may oc cur Where theend'of one web'is connected to the endof a new kroll of material.

After the materialhaspassed the hopper 89 it is in the form of. a continuous "web, portionsV of Vwhich are depressed into molds, which'm'olds are lled with semi-liquid unvul'canized 'latex 'rubber. Theconveyor .then advancesv the material vinto a curing oven 99 in which Vthe foam rubber is vulcanized by the applicationof heat. Any

. suitable or convenient supply of heat may be.,em-.;A ployed to iect vthe vulcanization, such' for example as heated air caused to flow `throughfthe oven 99, or if ,preferred dielectric4 heatingmay be used. As the'material leaves'the oven Smthe Weby is-caused to pass over-a stripper ro'll 95;..

While v.the endlessbelt mold .63.passes over the ..1101164. '..It may be'mentioned at'this time that .fthefoam rubber pad is relativelythinand is taperedl at onel sideto .what may be. defined. as

Ainasmuch .as the. rubber,

is at this time vulcanized tothe fabric web 55, removal of the structure from the mold is .accomplished `Without `subjecting 4`the .relatively fragile foam rubber pad to substantial stresses.

-Sincefthe latexfoam rubber wasapplied to the fabric-in. semi-liquid form, ,it ,Willhave-.penetrated the intersticesv ofthe. Woven .fabric Vso .that a very tight vulcanized bond iszeffected between the fabric and the pad.

The Vstripper roll 95 is locatedadjacent awash- `ing-and rinsing tank. 91.'in` whichthe .foam .rub-

vbedpad is repeatedly rinsed. Preferably, .pairs of squeezing rolls 98.-*and .99,...are `provided-.as y shown,` the rolls .98 being located. adjacent .the

bottom of the tank and the rolls 99 being. located labove;the=levelrof-liquidginfthe-tank. @Water-'may rbc employed in washing-the foam: zrubben pads and the. passage-.- ofa pads. .through :theorollsghas the ieiectioffthoroughly cleaning thefpads If desired,A :the: material may.r bey givenv an .additional step` .of cleaningebytan spray operation (not shown).

:Following the'vva'shing of lthe pad :theamaterial l isadvancedithrougha drying 'ovenliL -Inorder #to prevent-shrinking of! the, fabric :Weblduring f vdrying ,agpluralitycoftraveling tentering. :clips IDI :areg providedon endless chain 1.92 traveling aroundfsprocketf 193. 'Thestentering clips .are

-;.pivoted as indicated. at lllllaand are-,provided with .':projections on ilheinundei,l surface for; engaging ".:the edgesroff the .fabric web-55. .As fthe individual :clips-enter thedryinglovenlll. they engage the under-surface of rcams iwhich press 'the clips firmly against the fabric web. The tentering `.clips-are retained againstlateral movement and thus eectivelyprevent shrinkage of the fabric during its advance ,through the drying oven.

If desired, automatic means may befprovided for severing the vvveb as it. adVancesfronrthe dryingoven'so as to separate lthe foam rubberpads. It-Will'be observed/that' each foam rubber.; pad is thus. yprovided on va. Yreinforcing -backing fabric 'whichfin turn extends beyond .the edges of the foam` rubber padand is usedi to -formv a portion oftheenvelope-for receiving fibrous paddingfma- .terial. `The. backing'iseut transversely of .the f strip. between the .areas coveredebyfthefoam rubberwas shown inthe drawing; resulting in individual-pads of. fabric;.backed foam rubber in vwhich .the fabrice` area is larger .than the .Hibbert pad `thus providing--a'marginal skirt on all sidesfor attachment at assembly.

LItwwill=of course be appreciated .thatlthe .exact sh-ape and sizefof `ther-molds providedlintheebelt G3 maybe as desired and thatl in likemanner, the Mnurnber, size and arrangement oflblindfholesprovided at the undervside of the rrubber padmay-be selected ftofcontrol they resilientv properties. of the. completed pad.

YReferring now-.toi-Figure .10 there isillustrated the appearance.` of .the yreinforced rubber pad as it.. comes from .lthel assemblyv line. In.y .this case it will be .observedthat thefabric 56 isillustrated das retaining the. .configuration ofv the mold .and the upper surfaceofthe rubber pail-designated -.-56 :is tensionedfto .formethe upper4 portion ofthe ,envelope,the:upper-surface*of the rubber .pad f I 0l assumes a curvature corresponding.precisely .to the cross-section-of the mold.

In .accordance withl .the I present f inventionA the foam rubber pad occupies the intersticeslofnthe reinforcing fabric so that the .two in eect become an integral part. Since the fabric is provided .in effect asV a reinforcement forthe pad and as a lining for the mold, removal .of the pad from the mold is accomplished with a maximum `.ofK ease anda minimum of waste. Moreover, since the foam rubberpad is thus provided with v-a reinforcing fabric, the necessity .of binding -the relatively lthin andrweak edges vof the pad is avoided. .Thepresent pad results in covering the entire cushion with a 'thickness of rubber .determined bytherequirements. In other words, the rubber is thick-where it is required for resilience and is .relatively thin Where the maximum resilience .is not required; :thus .waste of rubber is avoided. The .present method in which .the rein-forcing fabricv and rubber .pad arel produced as aunitar'yv part avoids fthe step of reingreggio forcing the rubber pad after its formation and thus eliminates what has previously been an unnecessary and expensive extra step.

It will of course be appreciated that the use of the flexible fabric web 56 as an aid to stripping or separating the vulcanized rubber pad from the mold, does not depend upon the web being a woven fabric. Such web can be formed of any suitable iiexible sheet material. Thus if it is not desired to provide the completed pad with a backing of fabric, then fiexible sheet material such for example as paper or any suitable substitute therefor, plastic sheeting or the like, or even wire mesh may be employed. In any case, the fiexible sheet material will be employed to strip or separate the rubber pad 'from the mold, which it will do without damage to any part of said pad, including the tapered feather edge thereof. It will of course be obvious that the flexible sheet material may be wider than the mold as illustrated in the drawings, or it may be the same width as the mold, or it may be narrower than the mold. While in the embodiment illustrated and described in detail the backing fabric is illustrated as wider than the mold, this is for the reason that in the illustrated embodiment the pad is to be assembled into a seat cushion. Thus in this instance the fabric webbing is strong enough to serve as a reinforcement for the pad when the latter is applied to the padding of a seat cushion. However, the invention is not limited to the production of seat cushions or to the automotive field. Obviously, the invention could be used in other fields, for example in the construction of mattresses or other cushion assemblies where pads of this type may be desired, and in many cases as will be obvious, it may be desirable to produce a rubber pad which in final form need not be provided with a reinforcing backing.

The present method results in rapid production of reinforced foam rubber pads which are of uniform high quality. It substantially eliminates waste due to scrap and it further reducesY the subsequent steps of handling the pad toi.-

a minimum. As a consequence seat cushions are produced which are equivalent in quality to previously known foam rubber cushions and which may be produced with greatly increased efciency and therefore lower cost.

The drawings and the foregoing specification constitutes a description of the improved apparatus for producing seat pads, in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What we claim as our invention is:

1. An apparatus for forming foam rubber seat pads, a traveling conveyor comprising a plurality of spaced molds each having a plurality of upwardly extending mold cores, means for advancing a web of fabric to said conveyor, cutting means operable on the fabric as it is advanced to form a plurality of holes in the fabric corresponding in number and disposition to the cores of said molds and registerable therewith, means operable as said cut fabric moves in registration with said mold to press said fabric into said mold with the cores extending through the holes in said fabric, and means for thereafter filling the fabric lined mold cavities with unvulcanized rubber.

2. An apparatus for forming foam rubber seat I pads, a traveling conveyor comprising a plurality vances.

of spaced molds each having a plurality of upd wardly extending mold cores, means for advancing a web of fabric to said conveyor, cutting means operable on the fabric as it is advanced to form a plurality of holes in the fabric corresponding in number and disposition to the cores of said molds and registerable therewith, said last named means comprising blades disposed to form a plurality of intersecting cuts to form a hole having attached fabric tabs extending thereunto, means operable as said cut fabric moves in registration with said mold to press said fabric into said mold with the cores extending through the holes in said fabric, and means for thereafter filling the fabric lined mold cavities with unvulcanized rubber.

3. An apparatus for forming foam rubber seat pads, a traveling conveyor comprising a plurality of spaced molds each having a plurality of upwardly extending mold cores, means for advancing a web of fabric to said conveyor, cutting means operable on the fabric as it is advanced to form a plurality of holes in the fabric corresponding in number and disposition to the cores of said molds and registerable therewith, means operable as said cut fabric moves in registration with said molds to press said fabric into said molds with the cores extending through the holes in said fabric, said last named means comprising a platen having openings therein for receiving said mold cores, and means for thereafter lling the fabric lined mold cavities with unvulcanized rubber.

4. Apparatus of the character described comprising means for continuously advancing a web of fabric, a cutting station past which said web advances comprising a plurality of cutters effective to cut a plurality of spaced sets of holes in said fabric, a conveyor having a plurality of shallow depressed molds therein each of which has a plurality of mold cores corresponding in number and arrangement with a set of holes in the fabric, a presser element operable as said conveyor advances to move downwardly into each mold, forwardly therewith, upwardly therefrom, and then rearwardly to its initial position, said presser having a lower surface conforming to the shape of the mold and having openings for receiving the mold cores, means effective as said fabric-lined molds advance for filling them with unvulcanized foam rubber, and a vulcanizing chamber through which said conveyor advances.

5. Apparatus of the character described comprising means for continuously advancing a web of fabric, a cutting station past which said web advances comprising a plurality of cutters effective to cut a plurality of spaced sets of holes in said fabric, a conveyor having a plurality of shallow depressed molds therein each of which has a plurality of mold cores corresponding in number and arrangement with a set of holes in the fabric, a presser element operable as said conveyor advances to move downwardly into each mold, forwardly therewith, upwardly therefrom, and then rearwardly to its initial position, said presser having a lower surface conforming to the shape of the mold and having openings for receiving the mold cores, means effective as said fabric-lined molds advance for filling them with unvulcanized foam rubber, a vulcanizing chamber through which said conveyor advances, means for stripping said fabric web with the rubber vulcanized thereto from said molds, and means for washing and drying the material as it ad- 6. In apparatus of the character described, a belt mold comprising an endless belt of flexible, substantially non-extensible material, an outer mold layer of a rubber-like material carried by said belt, said mold layer having formed in its outer surface a series of shallow mold recesses, and a plurality of separate core elements projecting upwardly from the bottom of said recesses, the tops of said core elements being spaced below the tops of said recesses to form a molded body having one smooth surface and its opposite surface provided with a plurality of spaced apart recesses extending into said body.

7. Structure as defined in claim 6 in which said mold layer is silicone rubber.

8. An apparatus for forming foam rubber seat pads, and endless conveyor comprising a fiexible substantially non-extensible belt, an cuter layer of a rubber-like material having a series of spaced, shallow mold recesses therein, each of said mold recesses having a plurality of separate core elements projecting upwardly from the bottom of said recesses, means for advancing a web of fabric to said conveyor, cutting means oper-,- able on the fabric as it is advanced to form a plurality of holes in the fabric corresponding in number and disposition to the cores of said molds and registerable therewith, means operable as said cu't fabric moves in registration with said mold to press said fabric into said mold with the cores extending through the holes in said fabric, and means for thereafter filling the fabric lined mold cavities with unvulcanized rubber.

9. In apparatus of the character described, a belt mold comprising an endless belt of flexible, substantially non-extensible material, an outer mold layer of a rubber-like material carried by said belt, said mold layer having formed in its outer surface a series of mold recesses, and a plurality of separate core elements projecting upwardly from the bottom of said recesses, the

tops of said core elements being spaced below the tops of said recesses to form a molded body having one smooth surface and its opposite surface provided with a plurality of spaced apart recesses extending into said body.

10. In apparatus of the character described, a belt mold comprising an endless belt of flexible, substantially non-extensible material, an outer mold layer of a rubber-like material carried by said belt, said mold layer having formed in its outer surface a series of mold recesses having upwardly concave bottom walls, edges of which extend substantially to the outer surface of said mold layer to produce articles having tapered edges, and a plurality of separate core elements projecting upwardly from the bottom of said recesses, the tops of said core elements being spaced below the tops of said recesses to form a molded body having one smooth surface and its opposite surface provided with a plurality of spaced apart recesses extending into said body.

JOHN R. MILLAR. ROBERT J. STACK. CLARENCE J. DAVIES.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 1,650,981 Crouch Nov. 29, 1927, 1,751,430 Thomson Mar. 18, 1930 1,752,295 Felix Apr, 1, 1930 2,271,058 Binns Jan. 27, 1942 2,315,366 Daley et al Mar. 30, 1943 FOREIGN PATENTS Number Country Date 785,841 France May 27, 1935 

